Desired set temp past max on Minimax 400

Nov 16, 2014
Houston, Tx
My heater will only reach about 96 degrees inlet temp with either temp control knob set to max. If I turn the knob harder so I am past the end of the pot I can get it to relight but then it is in a non linear zone and it goes up to about 110 before shutting off. I have tried fiddling with the two pots on the back of the board which I have assumed are for trim but they have no detectable effect. How do I get the desired set point of 103 back into the range of the controls? Thoughts?